This application relates to a variable speed boost compressor for supplying cooling air for application in gas turbine engines.
Gas turbine engines are known and typically include a fan delivering air into a compressor where it is compressed and delivered into a combustor. In the combustor, the air is mixed with fuel and ignited. Products of this combustion pass downstream over turbine rotors, driving them to rotate.
As can be appreciated, components in the gas turbine engine can become quite hot. Thus, it is known to supply cooling air for selected components as a means of reducing operating temperature and enhancing durability. Historically, gas turbine engines have included a low pressure compressor and a high pressure compressor. The cooling air, particularly for high pressure turbine airfoils, has typically been tapped downstream of the high pressure compressor.
However, the cooling loads on the gas turbine engine are becoming higher. One recent example includes a gear reduction between a fan drive turbine and the fan. With the inclusion of this gear reduction, turbines rotate at a faster rate and the cooling load is increased.